Testing Of A Viscous-Damped Isolator

Item

Title
Testing Of A Viscous-Damped Isolator
Report Number
WL-TR-91-3078 Volume III, p. IAD-1 thru IAD-9
Creator
Allen, Bradley
Cunningham, David
Corporate Author
CSA Engineering, Inc.
Honeywell Satellite Systems
Date
1991
Date Issued
1991-08
Extent
9
Identifier
ADA241313
Format
1 online resource
Abstract
It is essential that accurate methods for testing mechanical properties be employed during the development of precision spacecraft isolation systems. Mechanical properties of the isolator will determine force transmission to the spacecraft; thus they are critical to its performance. This paper documents component-level tests performed on viscous-damped isolators developed by Honeywell Satellite Systems for a spacecraft reaction wheel isolator system. Two types of component-level tests were performed on the elements: direct stiffness measurements (often called mechanical impedance) and transmissibility tests. Direct stiffness measurements indicated linearity, linear stiffness, damping, and hysteresis. A custom test apparatus was designed for accuracy and repeatability. Stiffness deviations as small as 5 percent could be detected, and loss factors as low as 0.01 could be resolved with the direct stiffness measurements. Motion transmissibility measurements determined high-frequency isolation and verified stiffness and damping near the predicted resonance of the sprung payload. Although the suspension system consisted of eight isolators, tests were performed on a single unit. Motion was constrained to a single degree of freedom using a system of air bearings sliding on rails. The air bearing design possessed less than 0.4 grams of friction allowing verification of isolation properties to above 300 Hz and enabled transmissibility to be accurately measured over 4 orders-of-magnitude of input excitation.
Description
It is essential that accurate methods for testing mechanical properties be employed during the development of precision spacecraft isolation systems. Mechanical properties of the isolator will determine force transmission to the spacecraft; thus they are critical to its performance. This paper documents component-level tests performed on viscous-damped isolators developed by Honeywell Satellite Systems for a spacecraft reaction wheel isolator system. Two types of component-level tests were performed on the elements: direct stiffness measurements (often called mechanical impedance) and transmissibility tests. Direct stiffness measurements indicated linearity, linear stiffness, damping, and hysteresis. A custom test apparatus was designed for accuracy and repeatability. Stiffness deviations as small as 5 percent could be detected, and loss factors as low as 0.01 could be resolved with the direct stiffness measurements. Motion transmissibility measurements determined high-frequency isolation and verified stiffness and damping near the predicted resonance of the sprung payload. Although the suspension system consisted of eight isolators, tests were performed on a single unit. Motion was constrained to a single degree of freedom using a system of air bearings sliding on rails. The air bearing design possessed less than 0.4 grams of friction allowing verification of isolation properties to above 300 Hz and enabled transmissibility to be accurately measured over 4 orders-of-magnitude of input excitation.
Distribution Classification
1
Distribution Conflict
No
DTIC Record Exists
No
Illinois Tech Related
No
Photo Quality
Complete
Report Availability
Full text available
Type
article
Is Part Of
Proceedings of Damping '91: 13-15 February 1991 San Diego, California (GCA-1 through JCB-17)
Media
articleIAD

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Items with "Has Part: Testing Of A Viscous-Damped Isolator"
Title Class
Proceedings of Damping '91: 13-15 February 1991 San Diego, California (GCA-1 through JCB-17)